1. Field of the Invention
The invention is directed to an arrangement for the three-dimensional display or representation of scenes and/or objects based on planar layer images which have been obtained from different imaging planes which are offset with respect to the spatial depth of the scenes and/or objects.
2. Description of the Related Art
The procedures and arrangements known in the prior art for spatial representation of objects can be classified in three groups, in principle. In a first group, one of two images recorded from different viewing angles is allocated to one eye. Through suitable means, each eye is permitted to view the image allocated to it, but not the other image. These means ensure that each eye sees only the image allocated to it and are, for example, red-green spectacles, polarizing spectacles, and so forth.
It can also be ensured by means of appropriately arranged lenticular screens or prism screens such as split-image displays which split up the image that each eye is presented only with the image allocated to it.
However, a disadvantage consists in the fact that viewing positions and viewing distances are generally fixed at the outset and there is no possibility of accommodation of the eye. For this reason, viewing of the spatial representation achieved in this manner leads to fatigue. Further, the means required for viewing are sometimes quite elaborate, which increases cost.
In a second group of arrangements known from the prior art, the spatial representation is achieved in that the image and/or the projection of the image takes up volume. A substantial disadvantage in this case is that mechanically moving component assemblies are required which serve to project images at different spatial depths, for example, like rotating disks in a cathode ball, rotating LED surfaces or a rotating helix. This results in quite a high requirement of material and time and accordingly leads to unwanted costs since, on the one hand, precise manufacture is necessary for the moving component assemblies, whose movement must be carried out exactly, and, on the other hand, constructions of this type are also subject to wear resulting in increased expenditure on maintenance.
This group also includes a three-dimensional display device according to JP 62-77794 A which is formed from an image display device, a group of many fine, convex lenses with adjustable focal length, and another convex lens located opposite to the group of fine convex lenses. For example, the fine convex lenses are liquid crystal lenses with adjustable focal length, wherein control signals based on image depth information are applied to these lenses. When this arrangement is operated, various two-dimensional images, namely, images extending in the horizontal and vertical directions, are displayed on the image display device and can be viewed through the additional convex lens through corresponding control of the liquid crystal lenses or adjustment of focal lengths associated with the images so as to form an image which can be perceived in a three-dimensional manner.
However, the relatively elaborate optical-mechanical and optical-electronic construction and the rather large resulting constructional depth of 90 cm are disadvantageous. Also, an unwanted effect which is expected to occur is that the eye accommodated to large distances favors the raster of fine convex lenses or the raster of intermediate spaces between these lenses and does not perceive an undisturbed three-dimensional representation, which is what is actually desired. Further, the intended use on TFT displays (for miniaturization) may encounter problems, e.g., because of an unrealizable linear magnification of the optical system comprising the fine convex lenses and the additional convex lens.
Further, JP 07-64 020 A describes a three-dimensional display and a method for displaying by means of this display. According to this reference, three-dimensionally moving images can be displayed quickly and simply and can be viewed without spectacles in a large space.
For this purpose, there is a plurality of display elements which are outfitted with a convex lens having a short focal length, a light source and a stretching mechanism located between the lens and light source and which are arranged on a display surface. A three-dimensional image is generated in that the distance between the convex lenses and the light sources is changed by actuating the stretching mechanism, so that the position of the image of the light source formed by the convex lens is displaced. A three-dimensional image is formed by specifically changing the position of the virtual and real images of the light sources.
Apart from a construction which is also rather complicated in this case, a further disadvantage consists in that the aperture aberration of the convex lenses themselves is not corrected, resulting in low-quality imaging and small differences in image depths.
In a third group, images are imaged in volume. This is achieved, for example, by an acoustic-modulated concave mirror, computer-generated holograms using an acousto-optic modulator or making use of mercury vapor fluorescence by infrared excitation. These methods and arrangements are relatively complicated and therefore costly.